[ARC5] Vibrator Power Supplies

[John Young]

On the Apollo Program in 1966 we had failures of power transistors ion a DC to DC converter. The failure was an over current during switching due to transients. The fix was buy-pass capacitors around each switching transistor.. So no failures on all Apollo missions was the result.
John W4THQ

> On November 21, 2017 at 6:53 PM Dave Jackson <cjack93907 at razzolink.com> wrote:
>
>
> Bob:
>
> Agreed! I used to work on 1960-70 era Motorola Motracs and they would regularly blow the Germanium transistors for no apparent (at that time) reason.
>
> Sincerely,
>
> Dave WA4OBJ
>
> -----Original Message-----
> From: Bob kb8tq [mailto:kb8tq at n1k.org]
> Sent: Tuesday, November 21, 2017 10:39 AM
> To: Dave Jackson
> Cc: W9RAN at oneradio.net; arc5 at mailman.qth.net
> Subject: Re: [ARC5] Vibrator Power Supplies
>
> Hi
>
> Well, I can tell you that the normal vibrator supply typically had better reliability in the field than the early germanium based “transistor” supplies.
>
> Bob
>
> > On Nov 21, 2017, at 12:06 PM, Dave Jackson <cjack93907 at razzolink.com> wrote:
> >
> > Thanks Bob. I've been curious as to how the vibrator design compares
> > with the solid state MOSFET SMPS design as far as the contact life vs.
> > sparking (with the corresponding contact erosion). This will help
> > answer my questions.
> >
> > Sincerely,
> >
> > Dave WA4OBJ
> >
> > -----Original Message-----
> > From: arc5-bounces at mailman.qth.net
> > [mailto:arc5-bounces at mailman.qth.net] On Behalf Of Robert Nickels
> > Sent: Tuesday, November 21, 2017 8:00 AM
> > To: arc5 at mailman.qth.net
> > Subject: Re: [ARC5] Vibrator Power Supplies
> >
> > A lot of effort - both science and engineering - went into the design
> > of the low-cost DC-DC converter of the early 20th century, aka the vibrator power
> > supply. As the leading manufacturer of vibrators, P.R. Mallory Co. put
> > out a comprehensive design manual in 1947 that may be of interest to
> > anyone seeking to understand the design of such power
> > supplies: www.tubebooks.org/Books/mallory_vibe.pdf
> >
> > 73, Bob W9RAN
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